import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';

class Square extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      value: null,
    };
  }
  render() {
    return (
      <button className="square" onClick={() => this.props.onClick()}>
        {' '}
        {this.props.value}{' '}
      </button>
    );
  }
}

class Board extends React.Component {
  // constructor (props) {
  //     super(props);
  //     this.state = {
  //         squares: Array(9).fill(null),
  //         xIsNext: true
  //     }
  // }

  renderSquare(i) {
    return (
      <Square
        value={this.props.squares[i]}
        onClick={() => this.props.onClick(i)}
      />
    );
  }
  render() {
    // const winner = calculateWinner(this.state.squares);
    // let status;
    // if (winner) {
    //   status = "Winner: " + winner;
    // } else {
    //   status = "Next player: " + (this.state.xIsNext ? "X" : "O");
    // }
    //   const status = 'Next player: ' + (this.state.xIsNext ? 'x' : 'o');

    return (
      <div>
        {' '}
        {/* <div className="status">{status}</div> */}{' '}
        <div className="board-row">
          {' '}
          {this.renderSquare(0)} {this.renderSquare(1)} {this.renderSquare(2)}{' '}
        </div>{' '}
        <div className="board-row">
          {' '}
          {this.renderSquare(3)} {this.renderSquare(4)} {this.renderSquare(5)}{' '}
        </div>{' '}
        <div className="board-row">
          {' '}
          {this.renderSquare(6)} {this.renderSquare(7)} {this.renderSquare(8)}{' '}
        </div>{' '}
      </div>
    );
  }
}

class Game extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      history: [
        {
          squares: Array(9).fill(null),
        },
      ],
      stepNumber: 0,
      xIsNext: true,
    };
  }

  jumpTo(step) {
    this.setState({
      stepNumber: step,
      xIsNext: step % 2 === 0,
    });
  }

  handleClick(i) {
    const history = this.state.history.slice(0, this.state.stepNumber + 1);
    const current = history[history.length - 1];
    const squares = current.squares.slice();
    // 判断是否胜利或者此步骤已填写
    if (calculateWinner(squares) || squares[i]) {
      return;
    }
    squares[i] = this.state.xIsNext ? 'x' : 'o';
    this.setState({
      history: history.concat({
        squares: squares,
      }),
      stepNumber: history.length,
      xIsNext: !this.state.xIsNext,
    });
  }

  render() {
    const history = this.state.history;
    const current = history[this.state.stepNumber];
    const winner = calculateWinner(current.squares);

    const moves = history.map((step, move) => {
      const desc = move ? 'go to move #' + move : 'go to game start';

      return (
        <li key={move}>
          <button onClick={() => this.jumpTo(move)}> {desc} </button>{' '}
        </li>
      );
    });

    let status;
    if (winner) {
      status = `winner is ${winner}`;
    } else {
      status = `next player is ${this.state.xIsNext ? 'x' : '0'}`;
    }

    return (
      <div className="game">
        <div className="game-board">
          <Board
            squares={current.squares}
            onClick={(i) => this.handleClick(i)}
          ></Board>{' '}
        </div>{' '}
        <div className="game-info">
          <div> {status} </div> <ol> {moves} </ol>{' '}
        </div>{' '}
      </div>
    );
  }
}

function calculateWinner(squares) {
  const lines = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6],
  ];
  for (let i = 0; i < lines.length; i++) {
    const [a, b, c] = lines[i];
    if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
      return squares[a];
    }
  }
  return null;
}

// ========================================

ReactDOM.render(<Game />, document.getElementById('root'));
